Wireless communication devices or units such as subscriber devices and base transceivers providing data and voice services for users operating in corresponding systems are known. As these systems have evolved more sophisticated encoding and modulation schemes are being employed. Present systems often rely at least in part on schemes where orthogonality between signals is utilized to distinguish a signal from all others. A classic example of such a system is a spread spectrum system, such as a code division multiple access system where spreading codes that are orthogonal to each other are used to distinguish one signal from another. In theory when the proper code is used to despread the signal, the desired signal will exhibit a strong positive correlation and thus be recoverable while all others will simply be respread and thus contribute to interference, normally referred to as multiple access interference (MAI). In the end, MAI establishes an upper bound on system capacity for such systems.
In practice, due to the vagaries of wireless propagation and thus multiple propagation paths, receivers in spread spectrum systems often use rake receivers in order to recover desired signal energy from multiple paths. While the rake receiver approach will increase the desired signal energy it will have no impact on MAI, hence system capacity. Practitioners have contemplated decorrelating rake receivers. The decorrelating rake receiver attempts to increase desired signal energy and reduce MAI, thus improving or increasing system capacity. However known approaches for implementing decorrelating rake receivers are computationally intensive and typically rely on estimation techniques with unknown convergence properties for estimating parameters. A need exists for improved methods and apparatus to facilitate a decorrelating rake receiver.